Linux Sysadmin Blog » HowTo

Setup SSH Key Authentication

gerold — Sun, 17 Apr 2011 20:46:41 +0000

Setup ssh key authentication for password-less login between servers. For use by ssh/sftp users or scripts.

Source Server (or local system)

Generate RSA key for user on this system, you can also use DSA. This asks for key pass-phrase but you can leave it blank.

ssh-keygen -t rsa

This asks for location to place the generated key, by default it will be your home directory (ex: /home/your_username/.ssh/). This generates two files: id_rsa and id_rsa.pub. Content of id_rsa.pub is what we need to copy to destination server.

Destination Server (or remote server)

Check if you have the directory .ssh on your home (ex: /home/username/.ssh/), if not, create that directory.

ls ~/.ssh mkdir ~/.ssh
Check if you have existing file authorized_keys on your .ssh directory, if not create it.

ls ~/.ssh/ authorized_keys touch ~/.ssh/ authorized_keys

Copy content of id_rsa.pub that you created from your source/local server, or execute this command from your source/local server:

scp ~/.ssh/id_rsa.pub username@remote_host:~/.ssh/authorized_keys

Test your password-less login from source to destination server.

Setup SFTP-Only Access (Redhat-based Distro)

gerold — Tue, 12 Apr 2011 19:41:17 +0000

Setup sftp-only access on default Redhat/CentOS install. Use built-in sftp-server which is non-chrooted and easy to setup.

Server: Locate sftp-server binary and add to your list of valid shells on the system.

which sftp-server

Note: This will most likely give you this: /usr/libexec/openssh/sftp-server

echo /usr/libexec/openssh/sftp-server >> /etc/shells

Note: You may want to backup your /etc/shells first

User Accounts: Add or modify accounts to use sftp-server.

New User

useradd -s /usr/libexec/openssh/sftp-server sftponlyuser

Note: Important parameter there is the “-s /usr/libexec/openssh/sftp-server”, which sets the default shell for this account. By default you will have “/bin/bash”.

Existing User:

vi /etc/passwd

Find the user that you want to configure for sftp only access and edit its shell. For exampleyou will see a line “username:x:500:500::/home/username:/bin/bash” change “/bin/bash” to “/usr/libexec/openssh/sftp-server” and save. Note: You may want to backup your /etc/passwd file as well.

Moving Drupal site with CiviCRM

gerold — Mon, 11 Apr 2011 15:24:29 +0000

The common headache for beginners who try to move their Drupal site with CiviCRM is the CiviCRM configuration on new location or domain. I did this countless times and dealt with different problems before. I’ve read many online tutorials and how-tos, and I finally have my notes which is working for me everytime i move Drupal and CiviCRM site.

Let’s assume you already moved the databases (separate database for Drupal and CiviCRM as a recommended setup) and the files to new location and have set the correct file permissions as well. Here is the part that you need for your CiviCRM to work on new location and domain:

access your database and empty civicrm.domain:config_backend. You see this anywhere with CiviCRM guide.
update database details, site path/directory, and domain on civicrm.settings.php
emtpy sites/default/files/civicrm/template_c (or make this entire dir writable by web user)
login to you new Drupal site and visit these urls:
http://sitename/civicrm/menu/rebuild?reset=1
http://sitename/civicrm/admin/setting/updateConfigBackend?reset=1
Note: This will rebuild the settings for you – if not, repeat/review all the above steps.

Install ApacheSolr in Ubuntu for Drupal

gerold — Sun, 03 Apr 2011 19:26:25 +0000

I’ve written few Drupal ApacheSolr install guides here and this one is basically an install draft for Ubuntu.

Environment: Ubuntu 10.10, Apache, PHP, MySQL, Drupal 6.20

Things to install / setup: Solr, Tomcat6, ApacheSolr module for Drupal, and SolrPHPClient library

1.) Install Tomcat and setup your Tomcat admin user.

aptitude install tomcat6 tomcat6-admin tomcat6-common tomcat6-user vi /etc/tomcat6/tomcat-users.xml

/etc/init.d/tomcat6 restart

If all is good you will be able to access Tomcat admin at http://hostname:8080. Default page will show with links to admin section, etc.

2.) Install Solr

wget http://apache.rediris.es/lucene/solr/1.4.1/apache-solr-1.4.1.zip (check for updates)
unzip apache-solr-1.4.1.zip mkdir /usr/share/tomcat6/webapps cp apache-solr-1.4.1/dist/apache-solr-1.4.1.war /usr/share/tomcat6/webapps/solr.war cp -r apache-solr-1.4.1/example/solr /usr/share/tomcat6/solr vi /etc/tomcat6/Catalina/localhost/solr.xml

chown -r tomcat6.tomcat6 /var/lib/tomcat6 /etc/init.d/tomcat6 restart

You should see Solr access on your Tomcat admin/manager page (http://hostname:8080/manager/html).

3.) Connect Drupal Site to Solr (multi-core setup)

I already have a Drupal site with ApacheSolr module installed and SolrPHPclient library.

cp /path/drupal_site/sites/all/modules/apachesolr/schema.xml /usr/share/tomcat6/solr/conf/schema.xml cp /path/drupal_site/sites/all/modules/apachesolr/solrconfig.xml /usr/share/tomcat6/solr/conf/solrconfig.xml cp apache-solr-1.4.1/example/multicore/solr.xml /usr/share/tomcat6/solr/ mkdir /usr/share/tomcat6/solr/site_sample1 cp -r /usr/share/tomcat6/solr/conf /usr/share/tomcat6/solr/site_sample1/conf vi /usr/share/tomcat6/solr/solr.xml

chown -R tomcat6:root /usr/share/tomcat6/solr/ /etc/init.d/tomcat6 restart

Visit ApacheSolr settings of your Drupal admin and enter the configuration:
Solr Hostname: localhost
Solr Port: 8080
Solr Path: /solr/site1

To add new site to Solr:
mkdir /usr/share/tomcat6/solr/site_sample2 cp -r /usr/share/tomcat6/solr/conf /usr/share/tomcat6/solr/site_sample2/conf vi /usr/share/tomcat6/solr/solr.xml

That’s All.

Install Apache Solr and Tomcat for Drupal

gerold — Sun, 17 Oct 2010 10:10:55 +0000

Here’s my quick install guide for Solr, Tomcat, and Drupal ApacheSolr module for multiple sites. Mostly I based the steps below from the following sites: wiki.apache.org and drupalconnect.com.

Detailed Setup:

Drupal 6.19
ApacheSolr module 6-1.1
Apache Solr PHP Client Library: Rev.22
Solr 1.4.1
Tomcat 6.0.29
SunJDK 6update21
RHEL5.5×64

Install Process: Tomcat

Create solr user
Download Tomcat6
Extract to /opt/tomcat **this will be the $CATALINA_HOME directory, you can use any dir you want
Edit /opt/tomcat/conf/tomcat-users.xml to enable Tomcat login. See comments in this file.

Test run your Tomcat: /opt/tomcat/bin/catalina.sh run. Chown all Tomcat files to solr user (chown -R solr.solr /opt/tomcat). Default server setting will use port 8080, to customized edit the file /opt/tomcat/conf/server.xml. If you encounter error on “BASEDIR environment variable is not defined correctly…“, check permissions of .sh files inside /opt/tomcat/bin/ and make them executable (chmod 755 /opt/tomcat/bin/*.sh).
Add startup (init) script. Copy this Tomcat6 init file from Apache.org to /etc/init.d/tomcat6. Check and update variables like Java home, Tomcat directory, etc, if needed. Add to startup /sbin/chkconfig --add tomcat6 and /sbin/chkconfig tomcat6 on. Dependencies: redhat-lsb (or lsb-base?)
Visit your Tomcat Admin page. ex http://localhost:8080

Install Process: Solr

Download Solr
Extract to temporary location, ex: /opt/apache-solr-1.4.1
Copy /opt/apache-solr-1.4.1/dist/apache-solr-1.4.1.war to /opt/tomcat/webapps/solr.war
Copy /opt/apache-solr-1.4.1/example/solr directory to /opt/tomcat/solr **this will be the $SOLR_HOME directory, you can use any dir you want
Create file /opt/tomcat/conf/Catalina/localhost/solr.xml with the following configuration. Make sure paths are correct.

Install Process: ApacheSolr Drupal module and SolrPHP client

Install/enable Drupal ApacheSolr module. Drush, CVS, or traditional install – whatever you want. Example: /var/www/site1/sites/all/modules/apachesolr
Download SolrPHP client library

Configure Solr for Multi-Core Setup

Copy /var/www/site1/sites/all/modules/apachesolr/schema.xml to /opt/tomcat/solr/conf/schema.xml
Copy /var/www/site1/sites/all/modules/apachesolr/solrconfig.xml to /opt/tomcat/solr/conf/solrconfig.xml
Copy /opt/apache-solr-1.4.1/example/multicore/solr.xml to /opt/tomcat/solr/solr.xml
Create directory for each site and copy /opt/tomcat/solr/conf directory to each of them. Example:

mkdir /opt/tomcat/solr/site1 mkdir /opt/tomcat/solr/site2 cp -r /opt/tomcat/solr/conf /opt/tomcat/solr/site1/ cp -r /opt/tomcat/solr/conf /opt/tomcat/solr/site2/

Edit /opt/tomcat/solr/solr.xml with the following config:

Start or Restart Tomcat: /etc/init.d/tomcat6 start
Visit http://localhost:8080/ and go to you Solr App

Configure Drupal site:

Go to ApacheSolr settings http://localhost/admin/settings/apachesolr
Save your config and if all is good you’ll see message: Your site has contacted the Apache Solr server.

Solr host name: localhost Solr port: 8080 Solr path (for site1): /solr/site1

Configure your search index.

Remove Duplicate Packages in CentOS

gerold — Thu, 14 Oct 2010 11:15:25 +0000

I got a package dependency issue when updating our 64-bit CentOS server, which was caused by two perl packages installed (i386 and x86_64).
perl i386 4:5.8.8-32.el5_5.1 installed 28 M perl x86_64 4:5.8.8-32.el5_5.1 installed 34 M
I tried to remove it using rpm command but didn’t work (maybe i just don’t know the correct params with rpm). My solution to remove package was using yum “remove package_name.architecture“. Ex: yum remove perl.i386

Any other shortcuts in deleting duplicate packages?

HowTo remove a list of files

Marius — Fri, 09 Jul 2010 21:33:28 +0000

Here is a quick tip on how to remove a list of files. Let’s say you have the list of files inside a file called files_to_remove. Usually I would do something like this:
LIST=`cat files_to_remove`
and then
ls -al $LIST
just to check what is in the list and if it looks good.

And finally:
rm -vf $LIST

Problem Moving Drupal Site With SecurePages Module Enabled

gerold — Wed, 17 Feb 2010 12:41:23 +0000

I made a copy of Drupal6 site with SecurePages module installed and configured. This module is configured to redirect all or certain pages to https – depending on your configurations. For our setup we usually include the login and admin sections to redirect to https.

The problem is on the copied site that is on a new domain as we cannot login and go to the admin section because it redirect back to the source/original site. What we need is either disable the securepages module or update the domains. To do this, you need to access your database (ex: phpmyadmin, etc), go to variable table, and search for securepages configurations.

If you want to disable the module change:
securepages_enable s:1:"1";
to
securepages_enable s:1:"0";

Or if you want to update the domain change:
securepages_basepath s:30:"http://www.domain.com"; securepages_basepath_ssl s:31:"https://www.domain.com";
to
securepages_basepath s:30:"http://www.newdomain.com"; securepages_basepath_ssl s:31:"https://www.newdomain.com";

After making the above changes don’t forget to run the update.php (http://www.newdomain.com/update.php)

If you want to uninstall the module, try removing the securepages directory and run update.php.

Making Changes to Drupal Core

gerold — Mon, 15 Feb 2010 05:42:10 +0000

Although we made it a standard not to make any changes to Drupal core and core modules, there are times that our developers really need to make changes to core modules in order to add the required functionality. Cases like additional feature for ‘user’ or ‘comment’ modules and so on. At this state we can’t perform automatic update on our sites as we might overwrite the changes – so we need to do the update manually. Well, this is ok if you maintain one or two sites, but if you have more than 100 sites then it will take you some time.

What we did to eliminate this issue and be able to update the site automatically was Buy Ampicillin to create a copy of the original core modules (located in /modules), add our custom functionality, and put the modified copy into ‘contributed’ modules directory (/sites/all/modules). Drupal read the modules found on /sites/all/modules first and ignore the same copy (original) found on /modules. Also, may want to change the module info or the package name to separate the modified modules from the original ones – ex: modified_core, custom, etc. In the case that Drupal reads both of them, you can just disable the other one.

Here’s our policy on working with Drupal modules:
– contributed or community modules at /sites/all/modules
– custom made modules at /sites/all/modules/custom
– modified core modules at /sites/all/modules/core_modified

Hope this helps.

Upgrade to Fedora 12

max — Sun, 22 Nov 2009 20:58:02 +0000

Fedora release 12 became available to the public November 17, 2009. New features are plentiful and many are centred around KVM virtualization.

If you are like me and still running Fedora 10 or 11 and do not wish to wait till a yum based update is pushed out you can kick off your adventure into Fedora 12 land manually. Set aside at least Amoxil price an hour of time where you will not be able to use the PC while the update is taking place. First thing is to review Preupgrade Wiki Page, once you feel confident that your system is ready (enough space in /boot, created backups of your data) issue (as root):
yum update && yum install preupgrade
Followed by:
preupgrade-cli "Fedora 12 (Constantine)"
After a lengthy download, reboot and update process you should be looking at Fedora 12 login prompt.

If you used ext3 filesystem in your Fedora 10/11 system you can also migrate to ext4 filesystem by following the Fedora ext4 Wiki guide.